EP0421020A1 - Machine à engrenages pour utilisation comme pompe ou moteur - Google Patents

Machine à engrenages pour utilisation comme pompe ou moteur Download PDF

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Publication number
EP0421020A1
EP0421020A1 EP89118620A EP89118620A EP0421020A1 EP 0421020 A1 EP0421020 A1 EP 0421020A1 EP 89118620 A EP89118620 A EP 89118620A EP 89118620 A EP89118620 A EP 89118620A EP 0421020 A1 EP0421020 A1 EP 0421020A1
Authority
EP
European Patent Office
Prior art keywords
holes
machine
space
diaphragm
gear
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89118620A
Other languages
German (de)
English (en)
Other versions
EP0421020B1 (fr
Inventor
Angelo Zanardi
Daniele Mei
Vittorio Toselli
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sauer Sundstrand SpA
Original Assignee
Sauer Sundstrand SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sauer Sundstrand SpA filed Critical Sauer Sundstrand SpA
Priority to ES89118620T priority Critical patent/ES2061870T3/es
Priority to DE1989609046 priority patent/DE68909046T2/de
Priority to EP19890118620 priority patent/EP0421020B1/fr
Publication of EP0421020A1 publication Critical patent/EP0421020A1/fr
Application granted granted Critical
Publication of EP0421020B1 publication Critical patent/EP0421020B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/0003—Sealing arrangements in rotary-piston machines or pumps
    • F04C15/0023—Axial sealings for working fluid
    • F04C15/0026—Elements specially adapted for sealing of the lateral faces of intermeshing-engagement type machines or pumps, e.g. gear machines or pumps

Definitions

  • This invention relates to a gear machine for use as a pump or motor.
  • Gear machines are known to comprise a machine casing closed at its axial ends by respective covers and internally housing two mutually engaging gear wheels.
  • the gear wheels are provided on two rotatable shafts, namely the drive and driven shaft, which are supported by two bushes substantially of "8" shape.
  • Gear machines of the compensation type and of the fixed clearance type are in use.
  • seal gaskets are installed between the bushes and covers to define a space which is hydraulically connected to that part of the machine through which high-pressure fluid flows.
  • axial thrusts are created along the clearance walls defined between the gear wheel sides and the bushes and act on these latter, to be compensated by the axial thrusts created between the covers and the space defined by said gaskets.
  • a gear machine of the compensation type therefore allows the gap along the clearance walls to be taken up, allows the axial thrusts which arise along these latter to be balanced, and results in high volumetric efficiency for pumps and high mechanical efficiency for motors.
  • the machine has certain drawbacks due to the gasket preloading. In this respect, the preloading tends to urge the bushes towards the gear wheels so that on starting the machine there can be considerable friction between the bushes and gear wheels.
  • the machine For operation as a pump, the machine must be connected to a motor (normally electric) which has to overcome this initial separation friction and must therefore have a high starting torque. Consequently a powerful motor must be connected to the pump.
  • the object of the present invention is to provide a gear machine for use as a pump or motor which obviates the aforesaid drawbacks by operating as a fixed clearance machine on start-up, but as a compensation machine when under normal running for a predetermined fluid pressure.
  • a gear machine for use as a pump or motor of the type comprising a machine casing closed at each of its axial ends by a respective cover and internally housing two mutually engaging gear wheels provided on two rotatable shafts which are supported by two bushes and of which one extends to the outside of said machine casing, characterised in that between at least one of said covers and said machine casing there is installed a relatively elastic diaphragm in which there is provided a first hydraulic communication between a zone of said machine casing traversed by a high-pressure fluid and a first space delimited between said cover and said diaphragm by a first preloaded gasket assembly and having an area substantially equal to that defined area on said bushes on which axial thrusts are present during operation, and a second hydraulic communication between a zone of said machine casing traversed by low-pressure fluid and a second space delimited between said cover and said diaphragm by a second gasket assembly; the preload of said first gasket assembly being insufficient to
  • the reference numeral 1 indicates overall a gear machine for use as a pump or motor.
  • the machine 1 comprises a machine casing 2 closed at its axial ends by respective covers 3 and 4.
  • a diaphragm 5 of relatively elastic material such as aluminium is mounted between the cover 3 and the corresponding axial end of the machine casing 2.
  • the diaphragm 5 flexes towards the machine casing 2.
  • two mutually engaging gear wheels 6 provided on the central part of two rotatable shafts 7, one of which extends through the cover 4 to the outside of the machine casing 2.
  • the shafts 7 are supported by two "8"-shaped bushes 8 which are also housed in the machine casing 2.
  • the machine casing 2 has an internal shape which reproduces the perimetral shape of the assembly formed from the two gear wheels 6.
  • the casing 2 in correspondence with the zone of engagement between the gear wheels 6 the casing 2 comprises on opposite sides two ports 11, namely an inlet port and outlet port.
  • each bush 8 comprises cavities 12 which with the inner wall of the machine casing 2 define respective fluid channels.
  • each bush 8 comprises two parallel through holes 13, in each of which there is fitted a respective liner 14. Along the whole length of the holes 13 there is provided a recess 15, the purpose of which will be apparent hereinafter.
  • One of the shafts 7 has substantially the same axial length as the machine casing 2, whereas the other extends through a hole 16 in the cover 4 to the outside of the machine 1 to be connected to an electric motor or a mechanical or electromechanical user device according to whether the machine 1 is used as a pump or motor.
  • One gasket 18 makes contact with the inner face of the diaphragm 5 whereas the other makes contact with the inner face of the cover 4.
  • the machine 1 is assembled by tightening down four screws 21, only one of which is shown in Figure 1.
  • the screws 21 pass successively through a hole 22 provided in the cover 3, a hole 23 provided in the diaphragm 5 and a hole 24 provided in the machine casing 2, and are then screwed into a threaded bore 25 provided in the cover 4.
  • the head of the screws 21 abuts against a shoulder formed in the hole 22.
  • the diaphragm 5 comprises two through holes 31 which are coaxial with and face the bores 8 of the closer bush 8.
  • a hydraulic seal is determined mechanically between the bush 8 and diaphragm 5 by the effect of the fluid pressure.
  • the diaphragm 5 there are also provided four small holes, two of which, indicated by 36a, are in line with the channels defined by the cavities 12, whereas the other two indicated by 36b are in line with the gap between the bush 8 and the inner wall of the machine casing 2.
  • the first two holes 36a are symmetrical about a straight line orthogonal to that which joins the second two holes 36b and vice versa, as shown in Figure 3.
  • the cover 3 comprises two cylindrical recesses 41 coaxial with the holes 31 and communicating by way of two holes 42 which extend from the recesses 41 and intersect in the central part of the cover 3.
  • a threaded bore 43 extends from the recess 41 coaxial to the shorter shaft 7, and into which, on operation as a motor, there is screwed one end of a discharge pipe for drainage reasons which will be apparent hereinafter.
  • the bore 43 is engaged by a sealing plug.
  • the space in which the recesses 41 are provided is delimited by an annular seat 44 housing a retaining gasket 45.
  • the seat 44 and hence the gasket 45 are of "8" shape which substantially copies the perimetral shape of the bush 8.
  • the space 53 is delimited by the gasket 45, the spaces 54 and 55 oppose each other about the central part of the cover 3 and are delimited by the gaskets 47, and the spaces 56 and 57 oppose each other about the central part of the cover 3 and are delimited by a portion of the gasket 44 and a portion of the gasket 51.
  • the space 53 for hydraulic communication with the holes 31 is in a zone through which low-pressure fluid passes, as is evident from the fact that for motor operation the space 53 is connected to discharge through the bore 43.
  • the spaces 54 and 55 are in hydraulic communication with the cavity 12 in the low pressure zone and with the cavity 12 in the high pressure zone, according to the direction of rotation of the shafts 7.
  • the hole 36a communicating with the cavity 12 in the low pressure zone is shown by a dashed line ( Figure 3) and indicated by 61. It has a diameter greater than the other holes 36a and 36b.
  • an oblique bore 62 shown by dashed lines in Figures 1 and 2) which connects the hole 61 to the intersection of the holes 42.
  • an axial through bore 64 shown by dashed lines in Figure 1 is provided in the shorter shaft 7. If the machine is operated as a motor and is series-connected so that the fluid is not fed to discharge but to a further user device, the spaces 54 and 55 are simultaneously in a high-pressure zone. The spaces 56 and 57 are connected by the holes 36b to a high-­pressure zone defined within the machine casing 2.
  • a recess 65 coaxial with the shorter shaft 7.
  • the recess 65 is in hydraulic communication with a seal assembly 67 by way of an oblique bore 66.
  • a pressurised fluid enters the machine casing 2 through one port 11 to rotate the gear wheels 6 and convert hydraulic energy into mechanical energy.
  • the fluid is then discharged at a lower pressure through the other port 11. Any fluid which seeps along the holes 13 in the bushes 8 and specifically between the liners 14 and the wall of the holes 13 is drained to the outside through the bore 43.
  • the fluid which seeps along that bush 8 closer to the cover 3 flows out towards the recesses 41, which mutually communicate (hole 42) and of which one is provided along the bore 43.
  • the fluid which seeps along the other bush 8 flows out towards the recess 65 and also along the bore 16, and from this latter through the bore 66 to the recess 65. From this latter the fluid flows towards the bore 43 passing through the bore 64, the hole 31 and the recess 41 in succession.
  • the holes 36b communicate with the maximum pressure zone, which is that relative to those teeth of the gear wheel 6 distant from the engaging teeth.
  • the motor operation is of the fixed clearance type on starting, but with increasing pressure the diaphragm 5 flexes to an extent dependent on the pressure and on the size of the compensation area between the cover 3 and diaphragm 5. As the diaphragm 5 flexes it takes up the gap along the clearance walls. This gap is not totally taken up because part of the compensation pressure is used in overcoming the reaction produced by the flexure of the diaphragm 5. Summarising, a machine is provided in which the compensation system, necessary for obtaining high volumetric efficiency, does not penalise mechanical efficiency, to thus ensure highest overall efficiency. In particular, at vary low speed the high mechanical efficiency obtained by virtue of the low friction force along the clearance walls is vital in enabling the machine to start if there is a high resistant torque on the shaft 7.
  • one port 11 is connected to a fluid tank and the other port 11 is connected to a user device.
  • the mechanical energy of the motor shaft is converted into hydraulic energy in that the gear wheels 6 draw liquid from the tank and deliver it to the user device.
  • the pressure increases at the outlet port and in all those spaces communicating with it either by virtue of seepage along the bushes 8 and casing 2 as described heretofore or through the channel provided at the outlet port 11.
  • the pump When operating as a pump, there is again a gap along the clearance walls on starting, and this substantially reduces the friction which the electric motor must overcome for initial separation. As the pressure gradually increases, the diaphragm 5 flexes to partially take up the gap and partially compensate axial thrusts, to obtain a volumetric efficiency substantially higher than the initial value.
  • the pump behaves as a fixed clearance pump with all its associated advantages, whereas as pressure increases it behaves as a compensated pump with all the advantages deriving therefrom. It must be emphasized that the use of the machine 1 obviates the need to use a powerful motor to overcome initial separation friction as is required for balanced pumps of the prior art. At high pressure, the pump volumetric efficiency is greater than that of fixed clearance pumps of the prior art.
  • a second diaphragm 5 can also be installed as described with reference to operation as a motor.
  • the machine 1 comprises one extra component, it is of reduced manufacturing cost as no precision finishing machining is required to define the clearance along the clearance walls and the preload to apply to the gaskets on tightening-down during assembly.
  • the use of the machine 1 as described results in a saving in the members installed upstream or downstream thereof.
  • a respective diaphragm 5 of convenient material and thickness in relation to the flexing pressure can be connected to each cover 3 and 4.
  • the machine 1 is reversible, ie can operate with the gear wheels 6 rotating in one or other direction at choice.
EP19890118620 1989-10-06 1989-10-06 Machine à engrenages pour utilisation comme pompe ou moteur Expired - Lifetime EP0421020B1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
ES89118620T ES2061870T3 (es) 1989-10-06 1989-10-06 Maquina de engranajes para utilizar como bomba o motor.
DE1989609046 DE68909046T2 (de) 1989-10-06 1989-10-06 Zahnradmaschine zur Verwendung als Pumpe oder Motor.
EP19890118620 EP0421020B1 (fr) 1989-10-06 1989-10-06 Machine à engrenages pour utilisation comme pompe ou moteur

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19890118620 EP0421020B1 (fr) 1989-10-06 1989-10-06 Machine à engrenages pour utilisation comme pompe ou moteur

Publications (2)

Publication Number Publication Date
EP0421020A1 true EP0421020A1 (fr) 1991-04-10
EP0421020B1 EP0421020B1 (fr) 1993-09-08

Family

ID=8201992

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890118620 Expired - Lifetime EP0421020B1 (fr) 1989-10-06 1989-10-06 Machine à engrenages pour utilisation comme pompe ou moteur

Country Status (3)

Country Link
EP (1) EP0421020B1 (fr)
DE (1) DE68909046T2 (fr)
ES (1) ES2061870T3 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0512514A2 (fr) * 1991-05-07 1992-11-11 SAUER-SUNDSTRAND S.p.A. Machine à engrenages
US8776668B2 (en) 2010-04-16 2014-07-15 Robert Bosch Gmbh Machine housing of a hydraulic machine
US10634136B2 (en) 2016-07-26 2020-04-28 Eckerle Technologies GmbH Geared fluid machine with circumferential seal having first and second spaced apart seal limbs
CN112709692A (zh) * 2020-12-29 2021-04-27 西安精密机械研究所 一种提高海水泵容积效率的轴向补偿机构以及海水泵
CN113279956A (zh) * 2021-06-30 2021-08-20 合肥集源穗意液压技术股份有限公司 一种密封效果较好的镶联式齿轮油泵泵体

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB769763A (en) * 1954-05-20 1957-03-13 Air Equipement Improvements in or relating to gear pumps
US2842066A (en) * 1954-05-21 1958-07-08 Plessey Co Ltd Gear pump
FR1426585A (fr) * 1965-03-09 1966-01-28 Perfectionnements apportés à la réalisation d'appareils hydrauliques à engrenages, utilisés en particulier comme pompes ou comme moteurs
FR1533849A (fr) * 1966-08-15 1968-07-19 Borg Warner Pompes sous pression
FR1551320A (fr) * 1966-12-23 1968-12-27
FR2212861A5 (fr) * 1972-12-28 1974-07-26 Retel
FR2246188A5 (fr) * 1973-10-01 1975-04-25 Bosch Gmbh Robert

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB769763A (en) * 1954-05-20 1957-03-13 Air Equipement Improvements in or relating to gear pumps
US2842066A (en) * 1954-05-21 1958-07-08 Plessey Co Ltd Gear pump
FR1426585A (fr) * 1965-03-09 1966-01-28 Perfectionnements apportés à la réalisation d'appareils hydrauliques à engrenages, utilisés en particulier comme pompes ou comme moteurs
FR1533849A (fr) * 1966-08-15 1968-07-19 Borg Warner Pompes sous pression
FR1551320A (fr) * 1966-12-23 1968-12-27
FR2212861A5 (fr) * 1972-12-28 1974-07-26 Retel
FR2246188A5 (fr) * 1973-10-01 1975-04-25 Bosch Gmbh Robert

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0512514A2 (fr) * 1991-05-07 1992-11-11 SAUER-SUNDSTRAND S.p.A. Machine à engrenages
EP0512514A3 (en) * 1991-05-07 1993-07-07 Sauer-Sundstrand S.P.A. Gear machine
US8776668B2 (en) 2010-04-16 2014-07-15 Robert Bosch Gmbh Machine housing of a hydraulic machine
US10634136B2 (en) 2016-07-26 2020-04-28 Eckerle Technologies GmbH Geared fluid machine with circumferential seal having first and second spaced apart seal limbs
CN112709692A (zh) * 2020-12-29 2021-04-27 西安精密机械研究所 一种提高海水泵容积效率的轴向补偿机构以及海水泵
CN113279956A (zh) * 2021-06-30 2021-08-20 合肥集源穗意液压技术股份有限公司 一种密封效果较好的镶联式齿轮油泵泵体

Also Published As

Publication number Publication date
ES2061870T3 (es) 1994-12-16
EP0421020B1 (fr) 1993-09-08
DE68909046T2 (de) 1994-03-31
DE68909046D1 (de) 1993-10-14

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